Dmidecode tool read DMI (some say SMBIOS) table to fetch data and displays useful system information like hardware details, serial numbers and BIOS version, Processor etc. in a human-readable format. You may require root privilege to execute dmidecode command.

 

1. Basic Output of Demidecode

 

Below is the Demidecode command sample output.

# dmidecode 2.11
SMBIOS version fixup (2.31 -> 2.3).
SMBIOS 2.3 present.
45 structures occupying 1642 bytes.
Table at 0x000E0010.

Handle 0x0000, DMI type 0, 20 bytes
BIOS Information
        Vendor: Phoenix Technologies LTD
        Version: 6.00
        Release Date: 12/06/2006
        Address: 0xE78A0
        Runtime Size: 100192 bytes
        ROM Size: 64 kB
        Characteristics:
                ISA is supported
                PCI is supported
                PC Card (PCMCIA) is supported
                PNP is supported
                APM is supported
                BIOS is upgradeable
                BIOS shadowing is allowed
                ESCD support is available
               USB legacy is supported
                Smart battery is supported
                BIOS boot specification is supported

 

2. How to Get DMI Types

 

DMI Id gives us particular hardware information of the system. Dmidecode with options ‘-t ‘or ‘–type‘ and ‘Id‘ will provide us with the exact information. Id 6 will give us Memory Module information.

[root@rootadminz ~]# dmidecode -t 6
# dmidecode 2.11
SMBIOS version fixup (2.31 -> 2.3).
SMBIOS 2.3 present.

Handle 0x0009, DMI type 6, 12 bytes
Memory Module Information
        Socket Designation: RAM socket #0
        Bank Connections: 0 1
        Current Speed: Unknown
        Type: EDO DIMM
        Installed Size: 1024 MB (Single-bank Connection)
        Enabled Size: 1024 MB (Single-bank Connection)
        Error Status: OK

Handle 0x000A, DMI type 6, 12 bytes
Memory Module Information
        Socket Designation: RAM socket #1
        Bank Connections: 2 3
        Current Speed: Unknown
        Type: EDO DIMM
        Installed Size: Not Installed
        Enabled Size: Not Installed
        Error Status: OK

Handle 0x000B, DMI type 6, 12 bytes
Memory Module Information
        Socket Designation: RAM socket #2
        Bank Connections: 4 5
        Current Speed: Unknown
        Type: EDO DIMM
        Installed Size: Not Installed
        Enabled Size: Not Installed
        Error Status: OK

Handle 0x000C, DMI type 6, 12 bytes
Memory Module Information
        Socket Designation: RAM socket #3
        Bank Connections: 6 7
        Current Speed: Unknown
        Type: EDO DIMM
        Installed Size: Not Installed
        Enabled Size: Not Installed
        Error Status: OK

 

Following are the DMI types details.

         Type           Information
	----------------------------------------
          0		BIOS
          1		System
          2		Base Board
          3		Chassis
          4		Processor
          5		Memory Controller
          6		Memory Module
          7		Cache
          8		Port Connector
          9		System Slots
         10		On Board Devices
         11		OEM Strings
         12		System Configuration Options
         13		BIOS Language
         14		Group Associations
         15		System Event Log
         16		Physical Memory Array
         17		Memory Device
         18		32-bit Memory Error
         19		Memory Array Mapped Address
         20		Memory Device Mapped Address
         21		Built-in Pointing Device
         22		Portable Battery
         23		System Reset
         24		Hardware Security
         25		System Power Controls
         26		Voltage Probe
         27		Cooling Device
         28		Temperature Probe
         29		Electrical Current Probe
         30		Out-of-band Remote Access
         31		Boot Integrity Services
         32		System Boot
         33		64-bit Memory Error
         34		Management Device
         35		Management Device Component
         36		Management Device Threshold Data
         37		Memory Channel
         38		IPMI Device
         39		Power Supply

 

Instead of going with ‘type_id‘ you can also use keyword with ‘-t‘ argument to the dmidecode command. Following are the list of available keywords.

       Keyword     Types
      ------------------------------
       bios        0, 13
       system      1, 12, 15, 23, 32
       baseboard   2, 10
       chassis     3
       processor   4
       memory      5, 6, 16, 17
       cache       7
       connector   8
       slot        9

 

For example, to get the Cache information on the system, you can execute below command instead of Id 7.

[root@rootadminz ~]# dmidecode -t cache
# dmidecode 2.11
SMBIOS version fixup (2.31 -> 2.3).
SMBIOS 2.3 present.

Handle 0x000D, DMI type 7, 19 bytes
Cache Information
        Socket Designation: L1 Cache
        Configuration: Enabled, Socketed, Level 1
        Operational Mode: Write Back
        Location: Internal
        Installed Size: 16 kB
        Maximum Size: 16 kB
        Supported SRAM Types:
                Burst
                Pipeline Burst
                Asynchronous
        Installed SRAM Type: Asynchronous
        Speed: Unknown
        Error Correction Type: Unknown
        System Type: Unknown
        Associativity: Unknown

Handle 0x000E, DMI type 7, 19 bytes
Cache Information
        Socket Designation: L2 Cache
        Configuration: Enabled, Socketed, Level 2
        Operational Mode: Write Back
        Location: External
        Installed Size: 0 kB
        Maximum Size: 512 kB
        Supported SRAM Types:
                Burst
                Pipeline Burst
                Asynchronous
        Installed SRAM Type: None
        Speed: Unknown
        Error Correction Type: Unknown
        System Type: Unknown
        Associativity: Unknown

 

3. How to Get Memory Information

 

How do I get Memory information on the system and how much memory is supported by the system? The following command shows that the system can support the maximum 4GB of RAM.

 [root@rootadminz ~]# dmidecode -t 16
# dmidecode 2.11
SMBIOS version fixup (2.31 -> 2.3).
SMBIOS 2.3 present.

Handle 0x001D, DMI type 16, 15 bytes
Physical Memory Array
        Location: System Board Or Motherboard
        Use: System Memory
        Error Correction Type: None
        Maximum Capacity: 4 GB
        Error Information Handle: Not Provided
        Number Of Devices: 4

 

Note: From the keyword list the memory-related information IDs are 5, 6, 16 and 17.

 

4. How Do I Get BIOS information?

 

To get the BIOS information of the system, run the following command with ‘-t’ option.

[root@rootadminz ~]# dmidecode -t bios
# dmidecode 2.11
SMBIOS version fixup (2.31 -> 2.3).
SMBIOS 2.3 present.

Handle 0x0000, DMI type 0, 20 bytes
BIOS Information
        Vendor: Phoenix Technologies LTD
        Version: 6.00
        Release Date: 12/06/2006
        Address: 0xE78A0
        Runtime Size: 100192 bytes
        ROM Size: 64 kB
        Characteristics:
                ISA is supported
                PCI is supported
                PC Card (PCMCIA) is supported
                PNP is supported
                APM is supported
                BIOS is upgradeable
                BIOS shadowing is allowed
                ESCD support is available
                USB legacy is supported
                Smart battery is supported
                BIOS boot specification is supported

 

5. How Do I Get the Manufacturer, Model and Serial Number?

 

To get the information about Manufacturer, Model and Serial Number of system, use the following command as shown below.

[root@rootadminz ~]# dmidecode -t system
# dmidecode 2.11
SMBIOS 2.4 present.

Handle 0x0001, DMI type 1, 27 bytes
System Information
        Manufacturer: LENOVO
        Product Name: 9637C76
        Version: ThinkCentre M55e
        Serial Number: L9BT188
        UUID: 8015D37A-2F82-DC11-A3FB-8C6E4EBAD5CE
        Wake-up Type: AC Power Restored
        SKU Number: Not Specified
        Family: Not Specified

Handle 0x000F, DMI type 12, 5 bytes
System Configuration Options
        Option 1: Jumper settings can be described here.

Handle 0x0010, DMI type 15, 29 bytes
System Event Log
        Area Length: 432 bytes
        Header Start Offset: 0x0000
        Header Length: 16 bytes
        Data Start Offset: 0x0010
        Access Method: General-purpose non-volatile data functions
        Access Address: 0x0000
        Status: Valid, Not Full
        Change Token: 0x0000001A
        Header Format: Type 1
        Supported Log Type Descriptors: 3
        Descriptor 1: POST error
        Data Format 1: POST results bitmap
        Descriptor 2: Single-bit ECC memory error
        Data Format 2: Multiple-event
        Descriptor 3: Multi-bit ECC memory error
        Data Format 3: Multiple-event

Handle 0x0017, DMI type 23, 13 bytes
System Reset
        Status: Enabled
        Watchdog Timer: Present
        Boot Option: Do Not Reboot
        Boot Option On Limit: Do Not Reboot
        Reset Count: Unknown
        Reset Limit: Unknown
        Timer Interval: Unknown
        Timeout: Unknown

Handle 0x001F, DMI type 32, 20 bytes
System Boot Information
        Status:

 

Please run ‘man dmidecode‘ from the terminal or command prompt to know more about dmidecode.

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